Because View
Composer creates desktop images that share virtual disks with a base image, you
can reduce the required storage capacity by 50 to 90 percent.

View Composer uses a base image,
or parent virtual machine, and creates a pool of up to 2,000 linked-clone
virtual machines. Each linked clone acts like an independent desktop, with a
unique host name and IP address, yet the linked clone requires significantly
less storage.

Replica and Linked
Clones on the Same Datastore

When you create a linked-clone
desktop pool or farm of Microsoft RDS hosts, a full clone is first made from
the parent virtual machine. The full clone, or replica, and the clones linked
to it can be placed on the same data store, or LUN (logical unit number). If
necessary, you can use the rebalance feature to move the replica and
linked-clone desktop pools from one LUN to another or to move linked-clone
desktop pools to a Virtual SAN datastore or from a Virtual SAN datastore to a
LUN.

Replica and Linked
Clones on Different Datastores

Alternatively, you can place
View Composer replicas and linked clones on separate datastores with different
performance characteristics. For example, you can store the replica virtual
machines on a solid-state drive (SSD). Solid-state drives have low storage
capacity and high read performance, typically supporting tens of thousands of
I/Os per second (IOPS). You can store linked clones on traditional, spinning
media-backed datastores. These disks provide lower performance, but are less
expensive and provide higher storage capacity, which makes them suited for
storing the many linked clones in a large pool. Tiered storage configurations
can be used to cost-effectively handle intensive I/O scenarios such as
simultaneous rebooting of many virtual machines or running scheduled antivirus
scans.

For more information, see the
best-practices guide called
Storage Considerations
for VMware View.

If you use Virtual SAN
datastores or Virtual Volumes datastores, you cannot manually select different
datastores for replicas and linked clones. Because the Virtual SAN and Virtual
Volumes features automatically place objects on the appropriate type of disk
and cache of all I/O operations, there is no need to use replica tiering for
Virtual SAN and Virtual Volumes datastores.

Disposable Disks for
Paging and Temp Files

When you create a linked-clone
pool or farm, you can also optionally configure a separate, disposable virtual
disk to store the guest operating system's paging and temp files that are
generated during user sessions. When the virtual machine is powered off, the
disposable disk is deleted. Using disposable disks can save storage space by
slowing the growth of linked clones and reducing the space used by powered off
virtual machines.

Persistent Disks for
Dedicated Desktops

When you create
dedicated-assignment desktop pools, View Composer can also optionally create a
separate persistent virtual disk for each virtual desktop. The end user's
Windows profile and application data are saved on the persistent disk. When a
linked clone is refreshed, recomposed, or rebalanced, the contents of the
persistent virtual disk are preserved. VMware recommends that you keep
View Composer persistent disks on a separate datastore. You can then back up
the whole LUN that holds persistent disks.

Local Datastores for
Floating, Stateless Desktops

Linked-clone desktops can be
stored on local datastores, which are internal spare disks on ESXi hosts. Local
storage offers advantages such as inexpensive hardware, fast virtual-machine
provisioning, high-performance power operations, and simple management.
However, using local storage limits the
vSphere
infrastructure configuration options that are available to you. Using local
storage is beneficial in certain environments but not appropriate in others.

Note

The limitations
described in this section do not apply to Virtual SAN datastores, which also
use local storage disks but require specific hardware, as described in the
preceding section about Virtual SAN.

Using local datastores is most
likely to work well if the remote desktops in your environment are stateless.
For example, you might use local datastores if you deploy stateless kiosks or
classroom and training stations.

If you intend to take
advantage of the benefits of local storage, you must carefully consider the
following limitations:

You cannot use the View
Composer rebalance operation to load-balance virtual machines across a resource
pool.

■

You cannot store a View
Composer replica and linked clones on separate datastores, and, in fact, VMware
recommends storing them on the same volume.

If you manage local disk usage
by controlling the number of virtual machines and their disk growth, and if you
use floating assignments and perform regular refresh and delete operations, you
can successfully deploy linked clones to local datastores.

For more information, see the
chapter about creating desktop pools in the
ViewAdministration document.